Simple sugar concentration sensor and method

ABSTRACT

A glucose sensor comprising an optical energy source having an emitter with an emission pattern; a first polarizer intersecting the emission pattern; a second polarizer spaced a distance from the first polarizer and intersecting the emission pattern, the second polarizer rotated relative to the first polarizer by a first rotational amount Θ; a first optical detector intersecting the emission pattern; a second optical detector positioned proximal to the second polarizer, the first polarizer and the second polarizer being positioned between the optical energy source and the second optical detector, the second optical detector intersecting the emission pattern; a compensating circuit coupled to the second optical detector; and a subtractor circuit coupled to the compensating circuit and the first optical detector.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.14/822,524 filed Aug. 10, 2015, which is a continuation and claims thebenefit of U.S. patent application Ser. No. 14/293,356 filed Jun. 2,2014, now U.S. Pat. No. 9,101,308, which is a continuation and claimsthe benefit of U.S. patent application Ser. No. 13/950,054 filed Jul.24, 2013, now U.S. Pat. No. 8,743,355, which claims the benefit of U.S.Provisional Patent Application No. 61/714,731, filed Oct. 16, 2012; allof which are incorporated herein by reference in their entirety.

STATEMENT REGARDING FEDERALLY-SPONSORED RESEARCH OR DEVELOPMENT

Not applicable.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to monitoring of simple sugar (ormonosaccharide) content within a fluid. More specifically, the inventionuses an optical energy source in combination with polarizers todetermine the change in a sugar level (e.g., glucose) of a subject fluidrelative to a baseline concentration, such as blood.

2. Description of the Related Art

Simple sugar changes the polarization of the optical energy passingthrough it according to the equation Θ=α×L×C, where L is the travellength of the energy through the fluid in which the sugar isconcentrated, C is the sugar concentration, and α is a constant thatdepends on the type of sugar, wavelength of the energy, and the fluid.If L and α are known, by measuring the change in polarization of energypassing through a sugar-containing fluid relative to a baselinemeasurement, the sugar concentration of the fluid can be derived.

This principal may be used, for example, to non-invasively determine theglucose concentration of human blood. Normal blood has a non-zeroglucose concentration C, which causes a change in polarization forenergy passing through the blood. For a glucose concentration of 70mg/dL and an α=45.62 (×10⁻⁶) degrees/mm/(mg/dL), energy of wavelength633 nm and a 3.0 mm path length will have a rotation Θ of 0.00958degrees. Measuring the change in rotation caused by the sugar allowsderivation of the current sugar concentration.

SUMMARY OF THE INVENTION

The present invention may be used to monitor sugar (e.g., glucose) in afluid, and provides numerous advantages over traditional techniques thatrely on a standard polarization analyzer, which requires actively movingparts and angular resolution precision to 0.01 degrees. First, thepresent invention is non-invasive, which lowers the risk ofcontamination. Second, the present invention may provide an ability tostream real-time, continuous data. Third, the present invention providesa low operating cost.

The invention includes an optical energy source having an emitter withan emission pattern; a first polarizer intersecting the emissionpattern; a second polarizer spaced a distance from the first polarizerand intersecting the emission pattern, the second polarizer rotatedrelative to the first polarizer by a first rotational amount Θ; a firstoptical detector intersecting the emission pattern; a second opticaldetector positioned proximal to the second polarizer, the firstpolarizer and the second polarizer being positioned between the opticalenergy source and the second optical detector, the second opticaldetector intersecting the emission pattern; a compensating circuitcoupled to the second optical detector; and a subtractor circuit coupledto the compensating circuit and the first optical detector.

In one or more embodiments is described an apparatus for measuringchange in sugar concentration in a fluid relative to a baselineconcentration. The apparatus comprises a source of optical energy, saidsource having an emitter having an emission pattern. The apparatuscomprises a first optical detector spaced a distance from said source.The apparatus comprises a second optical detector collocated with saidfirst optical detector. The apparatus comprises a plurality ofpolarizers optically between said source and said detectors. Theplurality of polarizers comprises a first polarizer intersecting theemission pattern. The plurality of polarizers comprises a secondpolarizer rotated relative to the first polarizer by a first rotationalamount Θ, spaced a distance from the first polarizer, and proximal tosaid second optical detector, wherein said first polarizer is opticallybetween said source and said second polarizer. With the apparatus, thedistance between the first and second polarizers is sufficient to enablethe optical positioning of a volume of liquid intersecting said emissionpattern between said first polarizer and said second polarizer andoptically between the first polarizer and the first detector. Theapparatus comprises at least one circuit coupled to said first opticaldetector and said second optical detector. The at least one circuitcomprises a compensating circuit coupled to said second opticaldetector, a subtractor circuit coupled to said compensating circuit andsaid first optical detector, and a gain circuit coupled to saidsubtractor circuit. With the apparatus, in one or more embodiments, theat least one circuit further comprises a unity gain circuit coupled toand between said first optical detector and said subtractor circuit.With the apparatus, in one or more embodiments, the Θ is 45.028 degrees.With the apparatus, in one or more embodiments, the optical energysource is a near-infrared wavelength optical energy source. With theapparatus, in one or more embodiments, the optical energy source is ared-wavelength energy source. With the apparatus, in one or moreembodiments, the optical energy source is a LED. With the apparatus, inone or more embodiments, the optical energy source is a laser. With theapparatus, in one or more embodiments, the fluid is blood. With theapparatus, in one or more embodiments, the apparatus further comprises aform factor wearable around an ear, said form factor housing the opticalenergy source, the first polarizer, the second polarizer, the firstoptical detector, and the second optical detector. With the apparatus,in one or more embodiments, the Θ is between thirty-five and fifty-fivedegrees (inclusive) of rotation from a baseline rotation caused by abaseline concentration of a simple sugar in a fluid for energy travelinga length L through said fluid. With the apparatus, in one or moreembodiments, the Θ is between forty and fifty degrees (inclusive). Withthe apparatus, in one or more embodiments, the Θ is forty-five degrees.With the apparatus, in one or more embodiments, the plurality ofpolarizers consists of said first polarizer and said second polarizer.With the apparatus, in one or more embodiments, the optical energy isunmodulated. With the apparatus, in one or more embodiments, the opticalenergy consists of one unmodulated light wave.

In one or more embodiments described herein is method of detecting anamount of change of sugar concentration in a subject fluid relative to abaseline concentration. The method comprises directing optical energy ina first direction. The method comprises positioning the subject fluidbetween a first polarizer and a first detector, between said firstpolarizer and a second polarizer rotated relative to the first polarizerby a first rotational amount Θ, and between said first polarizer and asecond detector, wherein said second polarizer is positioned between thefirst polarizer and said second detector. The method comprises passingthe optical energy through the first polarizer to become once-polarizedoptical energy. The method comprises passing the once-polarized opticalenergy through the subject fluid to become rotated once-polarizedoptical energy. The method comprises detecting an intensity of therotated once-polarized optical energy. The method comprises passing atleast a portion of the rotated once-polarized optical energy through thesecond polarizer to become twice-polarized optical energy. The methodcomprises detecting the intensity of the twice-polarized optical energy.The method comprises providing a signal representative of a differencebetween the intensity of the rotated once-polarized optical energy andthe intensity of the twice-polarized optical energy. The methodcomprises correlating the signal to a sugar concentration. With themethod, in one or more embodiments, the optical energy is red-wavelengthoptical energy. With the method, in one or more embodiments, the opticalenergy is near-infrared optical energy. With the method, in one or moreembodiments, the first optical detector is collocated with said secondoptical detector.

In one or more embodiments is a system for measuring a change inpolarization of energy across a fluid. The system comprises a singlesource for emitting energy. The system includes a first polarizer forpolarizing the energy emitted from the source to provide a firstpolarized energy. The system includes a second polarizer for polarizingat least a portion of the first polarized energy and to provide a secondpolarized energy, wherein the second polarizer is rotated by arotational amount with respect to the first polarizer. The systemincludes a first detector for detecting the first polarized energyreceived a distance away from the first polarizer. The system includes asecond detector for detecting the second polarized energy. The systemincludes a module coupled with the first detector and the seconddetector, the module comprising a first unit for receiving output fromthe first detector and a second unit for receiving output from thesecond detector, the module comparing the first and second outputs. Withthe system, in one or more embodiments, the first unit of the modulecomprises an attenuator for reducing at least a portion of the outputfrom the first detector. With the system, in one or more embodiments,the second unit of the module comprises a compensator for boosting atleast a portion of the output from the second detector. With the system,in one or more embodiments, the system comprises a subtractor forreducing at least a portion of the output from the first detector. Withthe system, in one or more embodiments, the energy is in the form oflight emitted in a near infrared frequency range. With the system, inone or more embodiments, the polarizer is selected from a film, wiregrid, holographic wire grid, and beamsplitter. With the system, in oneor more embodiments, the second polarizer is rotated by a rotationalamount that is at least about 45 degrees or a multiple of about 45degrees. With the system, in one or more embodiments, the system furthercomprises a signal amplifier for amplifying output from the module. Withthe system, in one or more embodiments, the system is fitted to an earsuch that the first polarizer is on a first facing surface of an earwhile the second polarizer, the first detector, the second detector andthe module are on an opposing second facing surface of the ear.

In one or more embodiments is a system for measuring a change inpolarization of energy across a portion of a human body part. The systemcomprises a first polarizer for polarizing energy emitted from a sourceand to provide a first polarized energy to a first facing surface of thehuman body part. The system comprises a second polarizer for polarizingat least a portion of the first polarized energy received from the firstpolarizer when positioned on a second opposing facing surface of thehuman body part. The system comprises a first detector for detecting atleast a portion of the first polarized energy when received on thesecond opposing facing surface of the human body part. The systemcomprises a second detector for detecting at least a portion of thesecond polarized energy when received on the second opposing facingsurface of the human body part. The system comprises a module operablycoupled the first detector and the second detector on the secondopposing facing surface of the human body part. The module comprises afirst unit for receiving output from the first detector and a secondunit for receiving output from the second detector. The module utilizesthe outputs from the first and second units to derive a glucoseconcentration. With the system, in one or more embodiments, the secondpolarizer is rotated by a rotational amount with respect to the firstpolarizer. With the system, in one or more embodiments, the rotationalamount is between and includes 35 degrees and 55 degrees. With thesystem, in one or more embodiments, the system further comprises atleast a first band pass filter to filter the output from the firstdetector and a second band pass filter to filter the output from thesecond detector.

Still further is described an apparatus for measuring change in sugarconcentration in a subject fluid. The apparatus comprises a source ofenergy, the source having an emitter with an emission pattern. Theapparatus comprises a first detector spaced a distance from the source.The apparatus comprises a second detector collocated with said firstdetector. The apparatus comprises a plurality of polarizers between thesource and the detectors. The plurality of polarizers comprise at leasta first polarizer intersecting the emission pattern. The plurality ofpolarizers comprise at least a second polarizer rotated relative to thefirst polarizer by a first rotational amount Θ, spaced a distance fromthe first polarizer, and proximal to said second detector, wherein thefirst polarizer is between the source and the second polarizer. With theapparatus, in one or more embodiments, the distance between the firstpolarizer and the second polarizer enables the positioning of a volumeof liquid intersecting the emission pattern between the first polarizerand the second polarizer and optically between the first polarizer andthe first detector. With the apparatus, in one or more embodiments, theapparatus further comprising at least one circuit coupled to the firstdetector and the second detector. With the apparatus, the at least onecircuit comprises a compensating circuit coupled to the second detector,a subtractor circuit coupled to the compensating circuit and said firstdetector, and a gain circuit coupled to said subcontractor circuit. Withthe apparatus, in one or more embodiments, the compensating circuitcomprises a unity gain circuit coupled to and between the seconddetector and the subtractor circuit. With the apparatus, in one or moreembodiments, the compensating circuit comprises an attenuator coupled toand between first detector and the subtractor circuit. With theapparatus, in one or more embodiments, the plurality of polarizersconsists of the first polarizer and the second polarizer. With theapparatus, in one or more embodiments, the energy is unmodulated. Withthe apparatus, in one or more embodiments, the energy source is a LED.With the apparatus, in one or more embodiments, the Θ is betweenthirty-five and fifty-five degrees inclusive of rotation from a baselinerotation caused by a baseline concentration of a simple sugar in a fluidfor energy traveling a length L through said fluid. With the apparatus,in one or more embodiments, the Θ is between forty and fifty degreesinclusive.

An apparatus for measuring change in sugar concentration in a fluidrelative to a baseline concentration is also described herein. Theapparatus comprises a source of energy, said source having an emitterwith an emission pattern. The apparatus comprises a first detectorspaced a distance from said source. The apparatus comprises a seconddetector collocated with said first detector. The apparatus comprises afirst polarizer intersecting the emission pattern. The apparatuscomprises a second polarizer rotated relative to the first polarizer bya first rotational amount Θ, spaced a distance from the first polarizer,and proximal to said second detector, wherein said first polarizer isoptically between said source and said second polarizer. The apparatuscomprises a volume of liquid, said volume intersecting said emissionpattern and positioned between said first polarizer and said secondpolarizer and between said first polarizer and said first detector. Theapparatus comprises at least one circuit coupled to said first detectorand said second detector. The at least one circuit comprises acompensating circuit coupled to said second detector. The at least onecircuit comprises a subtractor circuit coupled to said compensatingcircuit and said first detector. The at least one circuit comprises again circuit coupled to said subtractor circuit.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a system diagram of an embodiment of the invention.

FIG. 2 is a circuit diagram of the circuit described with reference toFIG. 1.

FIG. 3 is the system diagram of FIG. 1 showing the embodiment in usewith a human ear.

FIG. 4A-4C show actual data from an embodiment of the present inventionused to derive sugar concentrations for three separate cases.

FIG. 5A-5C show the same data shown in FIGS. 4A-4C in a different form,with the unpolarized and polarized waveforms imposed on one another.

DESCRIPTION OF THE VARIOUS EMBODIMENTS

FIG. 1 shows one embodiment 20 of the invention, which comprises anoptical energy source 22, a first polarizer 24, a second polarizer 26spaced a distance from the first polarizer 24 having a rotation Θrelative to the first polarizer 24, a first optical energy detector 28,a second optical energy detector 30 collocated with the first detector28, and a circuit 46. Each of the first and second optical detectors 28,30 are oriented to receive optical energy passing through a space 32. Inthe preferred embodiment, the detectors 28, 30 are silicon detectors. Asused herein, “collocated” means being positioned adjacent each other sothat, all else being equal, light from a common source will enter eachof the detectors with approximately equal intensity. In addition,although the embodiment discloses the use of silicon detectors, othertypes of detectors may be used (e.g., photoresistors).

When actuated, the energy source 22 produces initial optical energy 34having an emission pattern 36. The energy source 22 is preferably a redlight source, such as a red light-emitting diode (LED) or a laser, butmay alternatively be near-infrared. Ultimately, the initial opticalenergy 34 must be of a wavelength that may be affected by the presenceof sugar in the subject fluid while also passing through the othervessel in which the fluid is contained.

The first polarizer 24 is positioned proximal to the source 22, suchthat the initial optical energy 34 passes through the first polarizer 24and becomes polarized energy 38. The polarized energy 38 traverses thespace 32 between the first and second polarizer 24, 26, where a firstportion 40 of the polarized energy 38 is detected by a first opticaldetector 28 and a second portion 42 of the polarized energy 38 passesthrough a second polarizer 26 to the second optical energy detector 30.Notably, first detector and second detector 28, 30 are collocated,despite the proximity of second polarizer 26 to the second detector 30.Because the space 32 is empty in FIG. 1, the polarized energy 38 passingthrough the space 32 is not rotated by, for example, the presence of asugar in a fluid.

Preferably, the first and second polarizers 24, 26 are alinearly-polarized film because such film is inexpensive compared toother available alternatives. Such film, however, is optimal for energywavelengths in the visible spectrum. Other polarizers may be used,provided that the selected wavelength of the energy source 22 is chosento optimally correspond. For example, an alternative polarizer may bewire-grid or holographic, which is optimally configured for use in thepresent invention with energy of near-infrared and infrared wavelengths.

Preferably, the difference in rotation between the polarizers 24, 26 isforty-five degrees (or an integral multiple of forty-five degrees) plusthe rotation caused by the baseline. In this optimal case, a change inconcentration relative to the baseline at least initially moves alongthe most linear portion of a sine wave, which makes detecting the changein rotation easier compared to moving further away from where the slopeof the wave is 1 and further towards where the slope is 0 (i.e., thecrest and troughs of the sine wave). For example, when used with abaseline glucose concentration 100 mg/dL over a length of L, Θ equals0.014 degrees. In this case, the rotation between the polarizers shouldbe 45.014 degrees. The greater the change in concentration from thebaseline, however, the more non-linear the correlation of the rotationto the change in concentration.

The first and second detectors 28, 30 are electrically coupled to thecircuit 46. The circuit 46 has a compensating circuit 48, a subtractorcircuit 50, and a gain circuit 52. The first detector 28 is directlycoupled to the subtractor circuit 50. The second detector 30 is coupledto the compensating circuit 48, which boosts the gain of the signalproduced by the second detector 30 by an amount sufficient to compensatefor the loss of intensity attributable to the portion 42 of polarizedenergy 38 passing through the polarized film and the effects ofpolarization due to the baseline concentrations in the fluid, but thecompensating circuit 48 does not compensate for the loss in intensityresulting from changes in polarization due to the concentration changefrom some baseline itself. The subtractor circuit 50 produces a signalthat is the difference between the signals received from the first andsecond detectors 28, 30. The gain circuit 52 amplifies the signal to ausable level.

Notably, in alternative embodiments, the compensating circuit 48 may bean attenuator coupled to the first detector 28 to equalize the intensityof the received optical energy, with the objective being that thedifference in energy seen by the first detector 28 and the seconddetector 30 relates to the rotation of the energy rather than itsamplitude. Similarly, the subtractor circuit 50 may be replaced by aWheatstone or similar bridge.

Referring to FIG. 2, the outputs of the first and second detectors 28,30 are provided to the circuit 46. The circuit 46 comprises thecompensating circuit 48 having a potentiometer Ro1, the subtractorcircuit 50, first and second 30-Hz low pass filters that included Ro1and C1, and Ro2 and C2, and the gain circuit 52. The subtractor circuit50 and the gain circuit 52 incorporate an OPA 211KP operationalamplifier IC 66. The low pass filters reject any noise at the detectors28, 30. Polarized output 53 and the unpolarized outputs 55 are fed tothe subtractor circuit 50, which comprises Ro3, Ro4, Rl3 and Rl4. Thesubtractor circuit output 54 is then provided to the gain circuit 52comprising Ro5 and C3. The final signal is provided at the gain circuitoutput 56. The embodiment includes an optional unity gain circuit 57 forphase-matching purposes.

FIG. 3 shows the embodiment 20 in use with a human ear 68, at least aportion of which occupies the space 32. The preferred orientation of theear 68 within the space 32 is so that the polarized energy 38 passesthrough the ear 68 generally parallel to a lateral axis, where L is thedistance along the axis of the measured fluid. For most human ears, L isapproximately three millimeters of capillary-rich and blood vessel-richskin.

When actuated, the energy source 22 produces initial optical energy 34having the emission pattern 36. The initial energy 34 passes through thefirst polarizer 24, and is of a wavelength to which the non-sugarcomponents of the ear 68 (i.e., skin, blood, tissue, cartilage) are, toat least some extent, transparent.

After passing through the first polarizer 24, the initial energy 34becomes polarized energy 38. Glucose within the blood in the ear 68,however, will cause a change in polarization of the energy 38 accordingto Θ=α×L×C, causing the rotated energy 70 exiting the ear to have afirst rotation Θ₁.

The intensity of a first portion 72 of the rotated energy 70 is detectedby the first detector 28. The intensity of a second portion 74 of therotated energy 70 passes through the second polarizer 26 and is detectedby the second detector 30. Each of the first and second detectors 28, 30produces a signal representative of the received intensity. Because theintensity of the rotated energy 70 received by the second detector 30 isonly the intensity of the rotated energy component passing through thesecond polarizer 26, by measuring the difference in intensities at thedetectors 28, 30, the rotation caused by the glucose in the ear 70 canbe derived, from which the changed in glucose concentration relative toa baseline can be determined.

To determine the baseline, prior to use, the embodiment 20 is calibratedto a baseline glucose concentration of seventy mg/dL (a “normal”concentration for human blood) by changing the potentiometer 60 tocompensate for the difference in intensities of energy received by thefirst and second detectors 28, 30. Thus, any change in measured rotationrepresents a change in glucose concentration from some baseline (e.g.,70 mg/dL).

An alternative embodiment of the invention is calibrated to a baselineglucose concentration of 100 mg/dL using wavelength of 650 nm, resultingin a rotation of 45.028 degrees of the second polarizer relative to thefirst polarizer. This results range of resulting rotation of thebaseline plus or minus 0.2 degrees for a glucose concentration ofbetween 30 mg/dL and 300 mg/dL. Thus, a glucose concentration of 30mg/dL will result in a rotational difference between the detectors of0.0096 degrees, whereas a glucose concentration of 300 mg/dL will resultin a rotational difference of 0.0273 degrees in the opposite directionof the direction of the 30 mg/dL concentration.

There are at least two methods for calibrating the invention. First andpreferably, during fabrication of each sensor, a sample control serum ora similar component that would rotate the polarization state a knownamount would be inserted in the space. This control would provide asimulated known glucose concentration for use in adjusting the device tothe proper calibrated settings. Alternatively, the user/wearer can takean initial reading with the sensor and additionally take anear-simultaneous reading with another glucose sensor (e.g., a bloodstick meter). This value from the other sensor would be input into thesensor with user input means such as a knobs, buttons and the likeconnected to a microcontroller.

FIGS. 4A-4C shows actual data from an embodiment of the invention usedto detect glucose concentrations of 75 mg/dL, 150 mg/dL, and 300 mg/DL.The left side of each example shows actual signals received from thepolarized detector 28 and the non-polarized detector 30. The right sideof each example shows the output of the subtractor circuit. Theembodiment is calibrated for a baseline of 75 mg/dL. In FIG. 4A, thesubtractor circuit averages to zero, indicating no change from thebaseline. In FIG. 4B, the subtractor circuit averages to approximately0.00005 Volts. In FIG. 4C, the output of the subtractor circuit averagesto approximately 0.0001 Volts, or twice the middle example, which isexpected give that the concentration of the bottom example is twice theconcentration of shown in FIG. 4B.

FIGS. 5A-5C show the same data depicted in FIGS. 4A-4C, but with theunpolarized and polarized waveforms on the same graph. FIG. 5Acorresponds to the data shown in FIG. 4A. FIG. 5B corresponds to thedata shown in FIG. 4B. FIG. 5C corresponds to the data shown in FIG. 4C.

The present disclosure includes preferred or illustrative embodiments inwhich specific sensors and methods are described. Alternativeembodiments of such sensors can be used in carrying out the invention asclaimed and such alternative embodiments are limited only by the claimsthemselves. Other aspects and advantages of the present invention may beobtained from a study of this disclosure and the drawings, along withthe appended claims.

I claim:
 1. A noninvasive system for measuring glucose, the systemcomprising: a light source emitting light in one of a red wavelength,near infrared wavelength, and an infrared wavelength, the light beingcapable of penetrating body tissue; a first polarizer proximal to thelight source for receiving all or at least a portion of the lightemitted directly from the light source; a second polarizer spaced apartfrom the first polarizer and positioned in a manner to receive polarizedlight provided by the first polarizer after the all or at least aportion of the light passes through the first polarizer, such that thesecond polarizer provides a second polarized light; a first detectorpositioned in a manner to detect at least some or all of the polarizedlight, in which the polarized light is polarized only from the firstpolarizer; and a second detector positioned in a manner to detect atleast some or all of the second polarized light, in which the secondpolarized light is provided by a first polarization with the firstpolarizer followed by a subsequent polarization with the secondpolarizer; the first detector being position proximal to the seconddetector, and one or more of the first detector and the second detectorbeing so adjusted that the polarized light to the first detector is of asimilar intensity as that of the second polarized light to the seconddetector.
 2. The noninvasive system of claim 1, wherein one or more ofthe first polarizer and the second polarizer are a linearly polarizedfilm.
 3. The noninvasive system of claim 1, wherein one or more of thefirst polarizer and the second polarizer are a wire grid polarizer. 4.The noninvasive system of claim 1, wherein one or more of the firstpolarizer and the second polarizer are a holographic polarizer.
 5. Thenoninvasive system of claim 1, wherein the first polarizer and thesecond polarizer are differentially rotated.
 6. The noninvasive systemof claim 1, wherein the first polarizer is rotated a rotation withrespect to the second polarizer, the rotation comprising about fortyfive degrees, or a multiple thereof.
 7. The noninvasive system of claim1, wherein the first polarizer is rotated a first rotation with respectto the second polarizer, the rotation comprising about forty fivedegrees, or a multiple thereof, in addition to a second rotation withrespect to the second polarizer, the second rotation caused bymeasurement of a control positioned between the first polarizer and thesecond polarizer to establish a baseline measurement of the system, thecontrol being capable of being penetrated or absorbed by the light fromthe light source.
 8. The noninvasive system of claim 1, wherein thefirst polarizer is rotated a first rotation with respect to the secondpolarizer, the first rotation comprising about forty five degrees, or amultiple thereof, with respect to the second polarizer, in addition to asecond rotation with respect to the second polarizer, the secondrotation caused by measurement of a control positioned between the firstpolarizer and the second polarizer to establish a baseline measurementof the system, the control comprising glucose in a concentrationconsidered normal for a human.
 9. The noninvasive system of claim 6,wherein the rotation is from 35 to 55 degrees, or a multiple thereof,and including 35 and 55 degrees, and multiples thereof.
 10. Thenoninvasive system of claim 1, further comprising a circuit, in which afirst output from the first detector, and a second output from thesecond detector are each provided to the circuit, the circuit comprisinga subtractor for producing at least a third output as a differencebetween the first output and the second output.
 11. The noninvasivesystem of claim 1, further comprising a circuit, in which a first outputfrom the first detector, and a second output from the second detectorare each provided to the circuit, the circuit comprising a Wheatstonebridge for producing at least a third output as a difference between thefirst output and the second output.
 12. The noninvasive system of claim1, further comprising a circuit, in which a first output from the firstdetector, and a second output from the second detector are each providedto the circuit, the circuit comprising a compensator for boosting atleast a portion of the second output.
 13. The noninvasive system ofclaim 1, further comprising a circuit, in which a first output from thefirst detector, and a second output from the second detector are eachprovided to the circuit, the circuit providing a third output, andfurther comprising a gain to amplify the third output.
 14. Thenoninvasive system of claim 1, further comprising a circuit, in which afirst output from the first detector, and a second output from thesecond detector are each provided to the circuit, the circuit comprisingan attenuator coupled to the first output.
 15. The noninvasive system ofclaim 1, further comprising a circuit, in which a first output from thefirst detector, and a second output from the second detector are eachprovided to the circuit, the circuit comprising at least a subtractorfor producing at least a third output as a difference between the firstoutput and the second output, a compensator for boosting at least aportion of the second output, and a gain to amplify at least the thirdoutput.
 16. The noninvasive system of claim 15, further comprising lowpass filters associated with the circuit to reduce noise from the firstdetector and the second detector.
 17. The noninvasive system of claim15, further comprising a unity gain circuit.
 18. The noninvasive systemof claim 1, wherein the system is for measuring glucose in the bodytissue, the body tissue positioned proximate to first polarizer andproximate to the second polarizer, and between the first polarizer andthe second polarizer.
 19. A method for measuring glucose, the methodcomprising: positioning a light source proximate to a first polarizer ina manner that light emitting from the light source is provided to thefirst polarizer, and the first polarizer provides polarized lighttherefrom, the light source emitting light in one of a red wavelength,near infrared wavelength, and an infrared wavelength, the light beingcapable of penetrating body tissue; positioning a first detector apartfrom the first polarizer in a manner to receive a portion of thepolarized light provided by the first polarizer, the first detectorproviding a first output, the polarized light received at the firstdetector being polarized only from the first polarizer; positioning asecond polarizer apart from the first polarizer in a manner for thesecond polarizer to receive a portion of the polarized light provided bythe first polarizer, the second polarizer providing a second polarizedlight, and the second polarized light provided by a first polarizationwith the first polarizer followed by a subsequent polarization with thesecond polarizer; positioning a second detector proximate to the seconddetector, and in a manner to receive all or a portion of the secondpolarized light provided by the second polarizer, the second detectorproviding a second output, the second polarized light received at thesecond detector being provided by the first polarization with the firstpolarizer followed by the subsequent polarization with the secondpolarizer; and adjusting one or more of the first detector and thesecond detector so the polarized light to the first detector is of asimilar intensity as that of the second polarized light to the seconddetector.
 20. The method of claim 19, further comprising: providing acircuit for receiving the first output and the second output, thecircuit comprising at least a subtractor for producing at least a thirdoutput as a difference between the first output and the second output, acompensator for boosting at least a portion of the second output, and again to amplify at least the third output.
 21. The method of claim 19,further comprising low pass filters associated with the first output andthe second output.
 22. The method of claim 19, wherein the adjusting theone or more of the first detector and the second detector is performedwhen providing a control proximate to the first polarizer and proximateto the second polarizer, and between the first polarizer and the secondpolarizer, the control having a first glucose concentration.
 23. Themethod of claim 19, wherein the adjusting the one or more of the firstdetector and the second detector is performed when providing a control,the control being proximate to the first polarizer and proximate to thesecond polarizer, and between the first polarizer and the secondpolarizer, and adjusting a potentiometer associated with the one or moreof the first detector and the second detector so intensity of thepolarized light to the first detector is similar or equal to intensityof the second polarized light to the second detector.
 24. A noninvasivesystem for measuring glucose, the system comprising: a light sourceemitting light; a first polarizer for receiving light emitted from thelight source; a second polarizer spaced apart from the first polarizerand positioned in a manner to receive a first polarized light providedby the first polarizer; a first detector positioned in a manner todetect the first polarized light from the first polarizer; and a seconddetector positioned in a manner to detect a second polarized light fromthe second polarizer; and the first detector being positioned proximalto the second detector and one or more of the first detector and thesecond detector being so adjusted that the polarized light to the firstdetector is of a similar intensity as that of the second polarized lightto the second detector.
 25. The noninvasive system of claim 24, whereinthe first polarizer and the second polarizer are differentially rotated.26. The noninvasive system of claim 24, wherein the first polarizer isrotated a rotation with respect to the second polarizer, the rotationcomprising about forty five degrees, or a multiple thereof.
 27. Thenoninvasive system of claim 24, wherein the system is for measuringglucose in the body tissue, the body tissue positioned proximate to thefirst polarizer and proximate to the second polarizer.
 28. Thenoninvasive system of claim 27, wherein the body tissue is between thefirst polarizer and the second polarizer.
 29. A method for measuringglucose, the method comprising: positioning a light source proximate toa first polarizer and a second polarizer in a manner that light emittingfrom the light source is provided to the first polarizer and the secondpolarizer; positioning a first detector apart from the first polarizerin a manner to receive polarized light provided by the first polarizer,the first detector providing a first output; positioning a seconddetector apart from the second polarizer in a manner to receivepolarized light provided by the second polarizer, the second detectorproviding a second output; adjusting one or more of the first detectorand the second detector so the polarized light to the first detector isof a similar intensity as that of the second polarized light to thesecond detector.
 30. The method for measuring glucose, according toclaim 29, wherein the first polarizer receives polarized light directlyfrom the light source and the second polarizer receives polarized lightfrom the first polarizer.